I made a copy of the Dutch thread.
221. Tobias Summerer (22) (ITF-130)
289. Andreas Beck (19) (ITF-50)
302. Philipp Petzschner (21) (ITF-8;doubles:1)
318. Simon Stadler (22) (ITF-8)
348. Sebastian Rieschick (19) (ITF-5)
603. Mihail Zverev (18) (ITF-11)
745. Matthias Bachinger (18) (ITF-354)
805. Aljoscha Thron (18) (ITF-100)
895. David Klier (18) (ITF-295)
Who is the best German talent? I decided to make the cut at 22 years, so that some successful players like Gremelmayr, Dorsch, Becker, Meffert, Greul and Berrer are not part of the poll. Of course, Kohlschreiber and Mayer are also 22, but they already had their breakthrough and the poll is about future top 100 players.
What I think is that Andi Beck will make the top 100. Thron is over-rated imo, he has only won matches on satellite level. Petzschner and Rieschick are smart players and fun to watch. Petzschner has a great "touch" and serve&volley, but he can't hit a hard backhand. The Dutch legend Jan Siemerink should be an example for him how to have success. Rieschick is an allrounder, he has the potential to have success on every surface.
So I would say, Beck and maybe Rieschick and Petzschner will make the top 100 in the future. But it looks like Germany has no future top 10 player.